For transportation, and particularly for air transport, the primary tool in combating global warming happens to be the same one prized by designers and manufacturers from the outset - efficiency.

The less fuel burned to motivate a business jet, the less greenhouse gases (GHGs) it contributes to the atmosphere. And as we move forward to accommodate ever more aircraft in the airspace system, fuel economy will be essential to keeping aviation´s overall output of CO2 - the principal GHG believed to be accelerating global warming - at the 2-percent level it is now.

As Business & Commercial Aviation reported last month in Part II of this series, the aviation industry is taking the lead in applying cutting-edge technology to a new generation of engines and airframes that are projected to yield quantum improvements in reducing fuel consumption, emissions and noise, operation and maintenance costs, while bettering performance. But these new products are not expected to enter service for at least five years, and even when they do, the majority of the fleet will still comprise technology ranging from the 1960s to the present and remain in service for decades to come.

In this installment of our "greening" series, we´ll examine procedures, strategies and airframe and engine modifications available to increase equipment and operations efficiency. First, the caveat we´ve provided in the first two installments: Regardless of your view regarding the global warming movement, these technologies and procedures represent tangible media for saving money as fuel prices continue to escalate. (As this is written, financier T. Boone Pickens is predicting $ 150-a-barrel oil by midsummer.) Your CFO, or to whomever in your company you are required to justify the cost of your operation, will love you for it.

Saving Fuel by Being Operationally Smart

The NBAA has been studying ways operators could lower their carbon footprints by saving fuel ever since global warming became a politically charged issue. "One of the most practical things we´ve been doing over the last six months is working with our members to identify the kinds of things that can be done operationally to reduce emissions and noise and minimize our impact on climate overall," said NBAA Vice President for Operations Steve Brown. "It gets down to very practical operational kinds of decisions, from single-engine taxiing to ATC procedures that could be modified on a local basis to save time and thus fuel," Brown elaborated. Unfortunately, not all business aircraft are designed to allow single-engine taxi due to hydraulic and electrical system considerations, but there are other options available to achieve the same purpose. "We are also promoting limited APU runs and, thus, not being wasteful with our fuel," Brown pointed out.

The NBAA is also addressing the handling of fuel - delivery and storage - since a number of its members maintain their own fuel farms. "When you look at the transfer of fuel," Brown said, "the whole chain of usage, there are lot things possible that could result in savings and thus lowered impact on the environment. So we are having a discussion about these options."

The NBAA is also urging airport managements to convert to electric-powered tugs and other ground vehicles. "So if there are ways to provide electrical vehicles or alternative-fueled vehicles that can reduce airport movement of fossil-fueled vehicles, we would encourage that, Brown said. "We are also talking to FBOs about this, as many are among our membership."

In terms of operations, Brown cited new ATC procedures that can be exploited by business aircraft operators to facilitate more direct routings, thus reducing flight times. Not only should this presumably please operators´ passengers, but will, over time, reduce their GHG emissions impact. One advantage of modern business aircraft is the ability to climb directly and rapidly to cruising altitudes above the flight levels customarily used by the airlines, thus freeing them from the constraints of having to use the airways and allowing true area navigation. Still, ATC managements have not always permitted operators to exercise the full capabilities of their aircraft to fly direct, restricting them to lower altitudes and circuitous routings. With recognition of global warming and the sobering wakeup call of rising fuel prices, the feds are taking a new look at revised ATC procedures that can promote fuel economy.

Designing ATC Procedures for Enhanced Efficiency

"There´s a whole area of activity concerning ATC procedures and new technology," said Brown, who once oversaw the entire ATC apparatus as a former FAA deputy administrator. "So we´re in a dialogue with the FAA on two fronts, first, the modernization of the system, and second, a shorter-term conversation to ensure the FAA gets sufficient resources in its budget to implement RNP approaches and satellite-based technology to allow shorter flights that save fuel. We´re letting Congress know that funding that technology is important, but once the FAA gets the money, we want to ensure they have a plan to implement these procedures. Of course the FAA has an environmental office headed by a talented manager who is doing a lot with ICAO and Europe to identify a global strategy for the reduction of CO2 and environmental impacts, as well as noise."

The NBAA is "looking across the whole fleet," Brown continued, "as most of our members actually operate turboprops. Other factors in our purview include the kind of technology that could be installed in aircraft in the future." Toward that end, the NBAA has maintained a close liaison with engine and airframe OEMs, lobbying for application of technology that can further reduce business aviation´s environmental impact. "So the NBAA´s initiative for global warming can be summarized as a joint strategy," Brown concluded, "working with the OEMs to encourage new technology over the long term, and in the short term, encouraging modified operations and procedures to reduce time in flight. That is, flying optimum profiles to minimize time en route and, wherever possible, engine operation."

Acknowledging that enhancing energy efficiency "has the dual benefit of improving both environmental and operational performance of the aviation sector," Dan Elwell, FAA assistant administrator for aviation policy, planning and environment, in testimony before Congress on April 2, acknowledged his agency must "accelerate" air traffic management efficiencies to reduce users´ fuel burn. Elwell credited the FAA´s RVSM initiative for having saved "millions of tons of carbon emissions," then cited new RNAV and RNP procedures, which he predicted would further save fuel and reduce noise.

"A good example of emissions reductions from aviation operational improvements is Continuous Descent Arrival, or CDA," Elwell told the House Select Committee on Energy Independence and Global Warming on Aviation Emissions. For an approach procedure, CDA allows a continuous descent path, rather than traditional step-downs in which cruise thrust must be repeatedly reinstated. The aircraft initiates the descent from cruising altitude in a near idle-thrust condition until reaching a predetermined stabilization point prior to short final and touchdown.

CDAs: a ´Win-Win´ Strategy

According to Elwell, CDA trials at Louisville Ky., have demonstrated fuel (and therefore GHG) savings averaging about 12 percent for the approach segment of a flight. Furthermore, use of CDAs at Atlanta Hartsfield Airport have yielded a claimed 1,300-pound reduction in CO2 for each approach.

CDA is a "win-win strategy," Elwell said, "having environmental and operational benefits that can reduce noise, emissions and fuel burn, as well as flight time." Cumulative measures like RNP/CDA instituted throughout the system can have "real impact," he maintained. "As additional advanced aircraft and air navigation procedures planned for the NextGen system the FAA´s long-awaited ATC modernization] are developed and deployed, we will see an even greater reduction in greenhouse gas emissions impacts from aviation."

Should NextGen comes on line as planned over the next five years, satellite-based ATC paired with Automatic Dependent Surveillance-Broadcast (ADS-B) technology is expected to yield even greater savings in fuel and emissions by promoting more direct routing. "In essence," Elwell said, "NextGen itself will improve environmental performance. We are already achieving early gains at a test program at Dallas-Fort Worth International Airport, where American Airlines´ use of NextGen-related procedures is reducing carbon dioxide emissions by levels equivalent to removing 15,000 cars from the road for a year."

To achieve lower aviation GHGs over the next 15 years to accommodate projected growth of the commercial fleet, the House Aviation Subcommittee in early May threw its weight toward NextGen as the most effective mechanism for that purpose over any form of mandated emissions-trading scheme, or "cap-and-trade" program, a la the European Union´s proposed ETS. Elwell also testified before this committee, pointing out that the U.S. aviation industry -- especially the airlines -- have reduced fuel consumption by some 11 percent over the past four years. On the other hand, Gerald Dillingham of the Government Accountability Office argued that the "issue is not past performance but future achievements" and suggested that NextGen held the potential to improve fuel efficiency and reduce GHG emission by 10 to 15 percent. Air Transport Association President Jim May also endorsed NextGen in written testimony.

The ATA has also urged Congress to increase funding to the FAA and NASA for environmental research and development programs, especially in the areas of advanced aerodynamics, lightweight construction materials and alternative fuels. Noting that aeronautics R&D funding has been slashed by half over the last 10 years, Ed Smith, GAMA´s senior vice president of international affairs and environment, also stressed the need for increased research budgets in the government´s aviation labs. He noted "Modernization of the ATC system is absolutely vital, whether we were having this debate about the environment or not. Modernization can produce tangible results, as well as getting rid of the fragmented airspace in Europe and ATC procedures like continuous-descent approaches."

Dirty Engines Pollute and Guzzle More Gas

During our recent visit to Pratt & Whitney in Hartford, Conn., Alan Epstein, vice president for technology and environment, said, "Carbon footprint is fuel burned, so anything you can do to reduce the amount of fuel you burn will reduce the footprint."To that end, Dr. Epstein claimed it is possible to gain a one-percent reduction in fuel burn by washing a dirty turbine engine. "For commercial engines, you want to do it twice a year," he said. "This also gives you EGT margin, which is basically fuel burn, so as your engine gets older, the margin goes down, which means you´re burning more fuel to make the same amount of thrust. That´s why the turbine temperature goes up. So if I wash my engine, I don´t burn as much fuel and I increase my TBO."

Notably, P&W unveiled in 2005 an environmentally friendly on-airframe engine-washing system dubbed EcoPower. Initially developed for the airlines, the portable system can be transported to an operator´s location and set up on the ramp to power-wash engines without having to remove them from their airframes. EcoPower is also claimed to recover every drop of water injected through the engine for later filtration and cleansing.

Will P&W make EcoPower available to business aviation operators? Anupam Bhargava, general manager of the Line Maintenance Services division of Pratt & Whitney Global Service Partners, answered that "We will soon broaden our scope to bring EcoPower technology to the business jet sector." Since launching the service, P&W has performed more than 1,000 washes on 22 military and commercial engine types.

"The other thing you can do (to promote engine efficiency and thus reduce carbon emissions) is, when you overhaul, have the overhaul done at the place that gives you the highest EGT margins," Epstein continued. "So you overhaul because either you´ve timed out life-limited components or the margin has gone to zero, but how close to new you get is dependent on the skill and knowledge of the overhaul shop, and not all of them give you the same margin, which is directly tied to fuel burn and life of the engine in terms of when you have to overhaul it again."

Given the longevity of good business aircraft, an entire aftermarket industry has emerged to provide various retrofits and upgrades designed to improve efficiency, performance and operating costs of older aircraft types and keep them viable. Many of these upgrades reduce fuel consumption and GHG emissions, as well as increase range. The most expensive of them involve outright engine exchanges, but some programs confine themselves to retrofitting newer-technology components, such as combustors and turbines, to older engines. Pratt & Whitney Canada, for example, administers such a program for some of its business aircraft and regional airliner turbines. "We continue to learn from the technology and bring it back to the older products," said John Saabas, P&WC executive vice president. "We have ongoing development programs that put lower-emissions combustors into the older engines that are available from block changes in production. We make these parts available for the aftermarket, and then it becomes a customer choice."

Examples of P&WC component retrofits include newer combustion liners for older PW100 turboprops and PT6A turboprops and turboshaft engines. "We are not regulated except for smoke," Saabas said, "so anything we do is to enhance the product as we move forward. There are SFC improvement programs for every engine model, specific and targeted emissions changes for the whole product line. I have several in development now and a couple waiting for production incorporation across the product portfolio that will attack overall emissions." P&WC also instructs operators on performance profiles, i.e., optimal ways to operate an engine, and flight paths that yield lower fuel burns, especially for fleet operators.

Dr. Epstein also pointed out that "Big Pratt" has developed upgrade programs for the PW4000 variant that powers the Airbus A300 and the V2500 narrow-body airliner engine in which P&W is a partner (the V2500 is built by a consortium of four OEMs and assembled in P&W´s Hartford plant). "These kits decrease the maintenance cost (of the older variants) with new designs that need less maintenance and provide a greater EGT margin," he said. "And the other yield of that is they give you better fuel consumption by a percent or more. The key is that the upgrades need to provide value to the customer, which is usually measured in operating cost; the decreased impact on global warming is a bonus."

Honeywell also markets component retrofits for older TFE731s found in more advanced variants of the popular turbofan. However, a company spokesman said these improvements are typically intended to enhance engine durability and extend TBOs rather than provide improvements in fuel consumption and emissions.

Blending Winglets for Performance (and Lots of Profit)

In terms of enhancing the efficiency of older airframes, particularly those designed without the benefits accorded by today´s powerful computational fluid dynamics (CFD) software, one of the most effective retrofits is the installation of what were originally known as Whitcomb Devices, or now simply as winglets. One of the notable business aviation aftermarket success stories in the past two decades has been Aviation Partners, the Seattle-based engineering company that developed so-called "blended" winglets for more than 10 types of business jets and airliners and numerous variants among them.

Starting with the Gulfstream II in 1993, Aviation Partners has extended its product line to the Hawker 800 and 800XP; Falcon 50, 900, 2000 and 2000LX; Boeing BBJ, 737-300, -500, -700, -800, and -900, 757-200, and soon, the 767-300ER and 777.

Company founder, CEO and Chairman Joe Clark said, "You can take an existing airplane anywhere from brand new to 40 years old and save in the area of 5 to 7 percent on fuel by reducing the wingtip vortex drag." He continued, "Arguably, ours are the most effective that have ever been designed, and they´re now on more than 2,400 airplanes." Clark said he believes that for the 767-300ER application, the Aviation Partners winglets will save operators 600,000 gallons of fuel annually.

A major endorsement for the firm´s blended winglet technology has been its adoption by airframe OEMs Boeing for the BBJ and 737 product lines and Dassault for the Falcon 2000LX and, soon, the 900LX. Both these manufacturers are installing the respective winglet kits on their assembly lines, Dassault as standard equipment and Boeing for airline customers that have specified them as an option on their 737s. Aviation Partners has also worked with airline customers in programs for specific types, American for the 767-300ER project and that carrier and Continental for the 777. "I probably get 25 calls a day from people wanting to save fuel," Clark said. "We will address the ones with the broadest market, like the classic Boeings. If an airline comes to us and the business model works, we´ll go do it."

Aviation Partners airline customers represent 88 different carriers from around the world. "The first were German carriers who had to deal with the green issue," Clark said. "They were being taxed on total noise and carbon footprint on an annual basis and could earn tax credits for reducing these, and that was one of the big drivers for us in that market. The payback for them is about two and a half to three years in fuel savings."

While the first airline users were European, the carrier that really put Aviation Partners on the map was Southwest, which to date has ordered 540 shipsets for its all-737 fleet. "Other big ones are Ryan Air, Continental and American," Clark said. "Continental is putting them on every aircraft it operates, including the Boeing 777, which we will also do."

World´s Largest Winglets for ´Fat Al´

Aviation Partners even took a crack at the Boeing 747 as a research project for widebodies back in the 1990s. Flight-tested aboard a 747SP, the winglets were 16 feet high with a chord of 13 feet at the wing attachment point. One of the prototypes is mounted on a stand at the entrance of Seattle´s Museum of Flight at Boeing Field. While the prototypes were constructed of fiberglass, if they´d gone into production, they would have been fabricated from carbon fiber with aluminum leading edges. "The performance was compelling," Clark said, "but at the time, with the fuel prices the way they were, we couldn´t make the business model work."

Explaining the effectiveness of his devices, Clark said, "On a big airplane there is a huge vortex generated by the wingtip. What we do is redistribute the lift on the wing, move it outward and make it more elliptical -- in other words, we change the aerodynamics of the wing."

It´s all about the transition, the shape and the blending, Clark said, the last being the aesthetically pleasing curvature from wingtip to winglet that is Aviation Partners´ signature contribution to the technology. "We move the vortex gradually up to the tip of the winglet where it becomes much smaller. The vortex is moved away from the plane, or flat part of the wing, and up to the tip of the winglet. So this reduces drag by 5 to 7 percent, sometimes more. On the Hawker, we got 7.7 percent."

Winglets are very heavily loaded, and their size depends on the strength designed into the wing, because as the winglet creates lift, it bends the wing upward. "So if you get too big a winglet, you then have to beef up the wing," Clark explained. "The optimum sizing depends on a lot of factors, but the most important one is the available strength left in the wing. There´s no difference from adding span, but the beauty of the winglet is you have less span to do the same job because it´s bent upward."

If you design winglets into a new wing, Clark claimed, wingspan can be reduced by 10 percent. "The magic is how you do the transition and shape the airfoils. We did it by prototyping and not in the wind tunnel, because wind tunnels do not accurately predict the performance -- never have, due to compressibility, smaller Reynolds numbers and cross flow."

Production winglets are fabricated from carbon fiber spars covered by carbon shells, all high-temperature cured, and fitted with stout aluminum leading edges. The Dassault and Hawker models do not feature multiple-spar construction but instead are fitted with a center spar surrounded by Nomex honeycomb for strength. GII winglets are 65 inches high, the Hawker product measures 44 inches and the Dassault item is close to the GII. Typically, the all-up weight of a shipset of winglets on the Hawker is around 160 pounds. The performance gain for the Hawker is 25 minutes more range on standard fuel; the Boeing 757 gets an additional 45 minutes.

"We design, certify, flight-test, and market and sell them," Clark said, "but all the manufacturing is subcontracted. We do it in Japan with Kawasaki, in Austria with Fischer, in England with GKN, and in the United States with Ducommon."

Blended winglets for business jets can be installed at a number of repair stations in the United States, including West Star Aviation and Duncan Aviation. On the BBJ, they are installed at the Boeing factory in Renton, Wash., as standard equipment. For the Gulfstream II, they are priced at $ 550,000 installed; for the Hawker series, $ 456,000; and for the Falcon 2000 series, $ 550,000.

For the future, Clark is evaluating a number of other aircraft types, including some Cessna products. "Not only that, but we are eying a number of airplanes already equipped with winglets that we feel we can improve, for example, the Challenger 604 or 300. And we´re considering some Airbus products, too."

In addition, Aviation Partners is continuing to evaluate the so-called "spiroid" winglet, akin to a Mobius Strip attached to the tip of a wing. "We are continuing to do new R&D programs like the spiroid winglet, which we are testing on a Falcon 50," Clark said. "Testing it on the Gulfstream, we got a 10-percent drag reduction. We anticipate that in five years we can certify it. Probably it will appear first on an airliner because they want the immediate payback since they fly so much. Southwest flies their aircraft 5,000 hours a year. With any wingtip device, the longer you fly, the greater the benefit."

Another tactic to promote efficiency, at least incrementally, is to keep the airframe clean and slippery, since a coating of surface dirt causes drag. While even an older paint job that´s been waxed several times may feel smooth to the touch, some detergents, rubbing compounds, wash brushes and contaminated cloths can over time rub abrasive particulates into the paint, resulting in micro-scratches, not only dulling paint but rendering it vulnerable to ultraviolet radiation and airborne contaminants (which can be blasted into the paint at several hundred miles per hour).

A polymer coating developed by Dow Corning in 2000 and applied with a procedure designed by ProguardPlus is designed to prevent this as well as preserve a paint job almost indefinitely with periodic servicing (but not re-application). In 2007, Matt Weisman, founder of Executive Air Fleet, and Jean-Clause Biget, formerly of Dassault Falcon Jet, launched CareJet Services to market the procedure, which does not require friction, heat or Teflon for application and results in a claimed high luster. The procedure, which can be applied at MRO facilities, FBOs or on-site at operators´ locations, is warranted for one year with optional extensions up to 48 months.

Weisman claims the polymer, called IE2000, is not a "cosmetic" but a "paint-saver." It fills in the naturally occurring peaks and valleys of the paint surface, leaving a flat coating that provides high reflectivity, resists UV and particulates, is paintable and only needs occasional washing. First time applications are priced from $ 10,000 for light jets to $ 20,000 for large ones.

Carbon Trading Schemes

Another strategy that business aviation operators can embrace to lower their carbon footprints is participation in a so-called carbon trading programs. Carbon trading, or offsetting, is based on the premise that an entity or activity that releases GHGs, especially CO2, into the atmosphere can compensate for it by purchasing credits from organizations that, in turn, invest in activities or programs that absorb or offset carbon, often in locations far from the entity that is purchasing the credits. The programs are also known as emissions-trading schemes, or ETSes.

Investments range from reforestation -- yes, tree planting -- to renewable energy projects as diverse as wind, solar, alternative fuels, carbon sequestration and even fuel-efficient cooking stoves for impoverished Third World countries to discourage the harvesting of trees for fuel. Conversely, carbon trading programs vary from major investments by corporations that produce significant amounts of CO2, for example, manufacturers using large amounts of fuel or electricity to produce their products and utilities operating coal-fired power plants, to relatively small credit purchasers, such as individuals looking to offset their personal impact from road or air travel.

Offsetting has been controversial since its inception, and a far from perfect mechanism. Even more controversial is the prospect of governments mandating participation in carbon- or emissions-trading schemes by entities that generate CO2 and other GHGs as a byproduct of their activities, such as aviation.

In Part I of this series, we described the ongoing argument between the European Union and ICAO and the United States concerning the E.U.´s intention to unilaterally mandate an ETS that would apply to any aircraft traversing its airspace because its legislators believe ICAO is not acting rapidly enough to curtail aviation´s contribution to global warming. The U.S. Congress is also investigating the possibility of a cap-and-trade scheme in the United States; however, the going political sentiment is leaning toward a voluntary program.

Meanwhile, Carl Burleson, the FAA´s aviation policy director for planning and environment, supports "market-based measures" to mitigate aircraft emissions as long as they´re voluntary. As Burleson told Aviation Daily, a sister publication, the FAA´s primary objection to the E.U.´s ETS is that it is being imposed unilaterally. The aviation authority is open to possible cap-and-trade schemes as long as they´re conceived through international consensus, i.e., under the auspices of ICAO. On the other hand, Burleson said, the rising cost of fuel is a market-based measure "more influential" than any ETS in convincing operators and the aviation industry to explore procedures and technology to reduce fuel consumption.

Another objection to the E.U. ETS proposal was voiced at the previously mentioned House Aviation Subcommittee hearing this spring by Rep. Peter DeFazio (D-Ore.) after a briefing by E.U. Ambassador John Bruton revealed that operators flying into European airspace would be held responsible and taxed for their carbon emissions for the entire duration of their flights, no matter how far away their origins. Imposing the ETS on foreign airlines operating into European airspace would force carriers to fund E.U. development projects including, ironically, the Union´s air-traffic management (ATM) modernization, DeFazio complained.

Nevertheless, voluntary participation in carbon trading programs is a mechanism available to operators, fractional aircraft owners and charter customers desiring to offset their individual contributions to CHG generation. Additionally, some airframe OEMs have instituted carbon offset programs for their customers.

At last year´s NBAA Convention, Bombardier Business Aircraft announced a carbon offset program in conjunction with U.K.-based Climate Care. Effective this February, the program was made available to new aircraft buyers as an option based on average annual utilization and aircraft type. Sold as part of the aircraft purchase price, the offset credit is good for one year´s operation. Meanwhile, Climate Care invests funds collected through the program in international renewable energy and energy efficiency projects.

Bombardier has enrolled its demo fleet and PartsExpress aircraft in the Climate Care program, an investment exceeding $ 250,000. And at last month´s European Business Aviation Convention and Exhibition (EBACE), Embraer unveiled its own carbon trading program.

Meanwhile, NetJets owners are being offered participation in a voluntary program to offset GHG emissions from their flights. Partnered with offset providers 3Degrees in the United States and Eco-Securities in Europe, the program adjusts fees to aircraft class and share size. Credits go toward reducing methane emissions at coal mines and dairy farms [Yes, cow flatulence, which believe it or not, is a major source of methane in the atmosphere! -- Ed.] and expanding electricity-generating wind farms. According to NetJets President Jim Christiansen, NetJets signed some 6.2 percent of its owners in the program in its first six months of operation.

And since creating its Environmental Committee last year, the National Air Transportation Association has launched its own emissions trading program titled Climate Initiative that includes purchasing carbon offsets for flight operations and a portfolio of best management practices for reducing energy consumption by ground handling services. Testifying before the House Aviation Subcommittee in May, NATA President Jim Coyne outlined efforts by his association´s members to limit their impact on the environment, pointing out that general aviation companies at large "remain dedicated to operating their businesses with safety and environment as their top priorities."

"We´re all doing this together," Steve Brown at NBAA said. "The task is to do it as responsibly as we can . . . in a way where we continue to be good stewards of the environment but continue to produce all the benefits of travel: business, social connections and quality of life. All of that is important to everyone on the planet."